Production of phosphoric acid and manganese containing catalysts



Patented Oct. 19, 1954 PRODUCTION OF PHOSPHORIC ACID AND MANGANESE CONTAINING CATALYSTS Julian M. Mavity, Hinsdale, and Mitchell S. Bielawski, Berwyn, Ill., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application April 12, 1949, Serial No. 87,132

11 Claims. 1

This invention relates to the manufacture of catalysts useful in accelerating various types of reactions among organic compounds. In a more specific sense, the invention is concerned with the production of a particular type of solid catalyst which has special properties both in regard to its activity in accelerating and directing olefin polymerization reactions, in its stability in service, and in its relatively low corrosive properties when employed in ordinary commercial apparatus comprising various types of steel.

An object of this invention is a method of producing a hydrocarbon conversion catalyst which has a high resistance to crushing during use.

Another object of this invention is a highly active catalyst suitable for use in the polymerization of olefinic hydrocarbons and in other hydrocarbon conversion reactions involving olefins.

One specific embodiment of this invention relates to a process for manufacturing a solid catalyst which comprises mixing a phosphoric acid, a siliceous adsorbent, and a manganese compound selected from the members of the group consisting of an oxide, 2. hydroxide, and a salt, drying and calcining the resultant mixture.

Another embodiment of this invention relates to a process for manufacturing a solid catalyst which comprises mixing a phosphoric acid, asiliceous adsorbent, and a manganese salt, drying and calcining the resultant mixture.

A still further embodiment of this invention relates to a process for manufacturing a solid catalyst which comprises mixing a phosphoric acid, a siliceous adsorbent, and a manganese sulfide, drying and calcining the resultant mixture.

An additional embodiment of this invention relates to a process for manufacturing a solid catalyst which comprises mixing a phosphoric acid, diatomaceous earth, and a manganese oxide to form a composite, drying and calcining said composite.

The essential and active ingredient of the solid catalysts which are manufactured by the present process for use in organic reactions is an acid of phosphorus, preferably one in which the phosphorus has a valence of 5. The acid may constitute 60% to about 75% or more of the catalyst mixture ultimately produced, and in most cases is over 50% by weight thereof. Of the various acids of phosphorus, ortho-phosphoric acid (HaPO4) and pyro-phosphoric acid (H4P2O7) find general application in the primary mixtures, due partially to their cheapness and to the readiness with which they may be procured-although the invention is not restricted to their use but may Cir employ any of the other acids of phosphorus insofar as they are adaptable. It is not intended to infer, however, that the different acids of phosphorus, which may be employed will produce catalysts which have identical eifects upon any given organic reactions as each of the catalysts produced from different acids and by slightly varied procedure will exert its own characteristic action.

In using ortho-phosphoric acid as a primary ingredient, different concentrations of the aqueous solution may be employed from approximately to or acid containing some free phosphorus pentoxide may even be used. By this is meant that the ortho acid may contain a definite percentage of the pyro acid corresponding to the primary phase of dehydration of the ortho phosphoric acid. Within these concentration ranges, the acids will be liquids of varying viscosities, and readily mixed with adsorbent materials. In practice it has been found that pyrophosphoric acid corresponding to the formula H4P2O7 can be incorporated with siliceous adsorbents at temperatures somewhat above its melting point (142 F.) and that the period of heating which is given to the pyro acid-adsorbent mixtures or to mixtures of other polyphosphoric acids and siliceous adsorbents may be different from that used when the ortho acid is so employed.

Triphosphoric acid which may be represented by the formula H5P3010 may also be used as a starting material for preparation of the catalysts of this invention. These catalytic compositions may also be prepared from the siliceous materials mentioned herein and phosphoric acid mixture containing ortho-phosphoric, pyro-phosphoric, tri-phosphoric, and other poly-phosphoric acids.

Another acid of phosphorus which may be employed in the manufacture of composite catalysts according to the present invention is tetra-phosphoric acid. It has the general formula HsP4O1a which corresponds to the double oxide formula 3H2O.2P2O5 which in turn may be considered as the acid resulting when three molecules of water are lost by four molecules of ortho-phosphoric acid 11131 04. The tetra-phosphoric acid may be manufactured by the gradual and controlled dehydration by heating of ortho-phosphoric acid or pyro-phosphoric acid or by adding phosphorus pentoxide to these acids in proper amounts. When the latter procedure is followed, phosphorus pentoxide is added gradually until it amounts to 520% by weight of the total water present. After a considerable period of standing at ordinary temperatures, the crystals of the tetra-phosphoric acid separate from the viscous liquid and it is found that these crystals melt at approximately 93 F. and have a specific gravity of 1.1886 at a temperature of 60 F. However, it is unnecessary to crystallize the tetra-phosphoric acid before employing it in the preparation of the solid catalyst inasmuch as the crude tetraphosphoric acid mixture may be incorporated with the siliceous adsorbent and other catalyst ingredients.

The materials which may be employed as adsorbents or carriers for acids of phosphorus are divided roughly into two classes. The first class comprises materials of predominantly siliceous character and includes diatomaceous earth, kieselguhr, and artificially prepared porous silica. The second class of materials which may be employed either alone or in conjunction with the first class comprises generally certain members of the class of aluminum silicates and includes such naturally occurring substances as various fullers earths and clays such as bentonite, montmorillonite, acid treated clays and the like. Each adsorbent or supporting material which may be used will exert its own specific influence upon the net effectiveness of the catayst composite which will not necessarily be identical with that of other members of the class.

Catalysts may be prepared from an acid of phosphorus such as ortho-phosphoric acid, pyrophosphoric acid, tri-phosphoric acid, or tetraphosphoric acid, and a siliceous adsorbent containing a manganese compound selected from the members of the group consisting of an oxide, a hydroxide, and a salt, the latter including particularly a carbonate, a sulfide, and a halide, such as a chloride or bromide. These mentioned starting materials used in this catalyst preparation process are subjected to the successive steps of mixing the manganese compound with the siliceous adsorbent, and thereafter mixing the phosphoric acid with the finely divided relatively inert carrier containing the manganese compound and generally maintained at a temperature of from about 50 to about 450 F. to form a rather wet paste, the'acid ordinarily being in major proportion by weight. Also the manganese compound may be added first to the phosphoric acid or the catalyst ingredients may be mixed in any order.

The resultant wet paste formed from the phosphoric acid, siliceous adsorbent, and manganese compound is then formed into shaped particles by extrusion or other suitable means and the resultant particles are then dried at a temperature of from about 200 to about 500 F. to form a substantially solid material which is then calcined further at a temperature generally of from about 500 to about 1000 F. for a time of from about 0.25 to about hours. The calcining may be carried out by heating in a substantially inert gas, such as air, nitrogen, and the like.

The resultant catalyst which has been calcined is active for polymerizing olefinic hydrocarbons, particularly for polymerizing normally gaseous olefinic hydrocarbons to form normally liquid hydrocarbons suitable for use as constit uents of gasoline. When employed in the conversion of olefinic hydrocarbons into polymers, the calcined catalyst formed as herein set forth, is preferably employed as a granular layer in a heated reactor, which is generally made from steel, and through which the preheated olefincontaining hydrocarbon fraction is directed. Thus the solid catalyst of this process'may be 4 employed for treating mixtures of olefin-containing hydrocarbon vapors to effect olefin polymerization, but this same catalyst may also be used at operating conditions, suitable for maintaining liquid phase operation during polymerization of olefinic hydrocarbons, such as butylenes, to produce gasoline fractions. Thus when employed in the polymerization of normally gaseous olefins, the formed and calcined catalyst particles are generally placed in a vertical, cylindrical treating tower and the olefin-containing gas mixture is passed downwardly therethrough at atemperature of from about 350 to about 550 F. and at a pressure of from about to about 1500 pounds per square inch when dealing with olefin-containing materials such as stabilizer reflux which may contain from approximately 10 to 50% or more of propylene and butylene. When operating on a mixture comprising essentially butanes and butylenes, this catalyst is efiective at conditions favoring the maximum utilization of both normal butylenes and isobutylene which involves mixed polymerization at temperatures of from approximately 250 to about 325 F. and at pressures of from about 500 to about 1500 pounds per square inch.

In utilizing the catalyst of this invention for promoting miscellaneous organic reactions, the catalyst may be employed in essentially the same way as it is used when polymerizing olefins, in case the reactions are essentially vapor phase and it may be employed, in suspension, also in liquid phase in various types of equipment.

With suitable modifications in the details of operation, the present type of catalyst may be employed in a large number of organic reactions, including polymerization of olefins as already mentioned. Typical cases of reaction in which the present type of catalyst may be used are the alkylation of cyclic compounds with olefins, the

cyclic compounds including aromatics, polycyclic 7 compounds, naphthenes, and phenols; condensation reactions such as those occurring between ethers and aromatics, alcohols, and aromatics, phenols and aldehydes, etc. Reactions involving the hydro-halogenation of unsaturatedorganic compounds, isomerization reactions, ester formation by the interaction of carboxylic acids and olefins, and the like. The specific procedure for utilizing the present type of catalyst in miscellaneous organic reactions will be determined by the chemical and physical characteristics and the phase of the reacting constituents.

During use of these catalysts in vapor phase polymerizations and other vapor phase treatments of organic compounds, it is often advisable to add small amounts of moisture to prevent excessive dehydration and subsequent decrease in catalyst activities. In order to substantially prevent loss of water from the catalyst an amount of water or water vapor such as steam is added to the charged olefin-containing gas so as to substantially balance the vapor pressure of the catalyst. This amount of water vapor varies from about 0.1 to about 6% by volume of the organic material charged. 'I

Solid phosphoric acid catalysts which have been prepared heretofore by calcining composites of a siliceous adsorbent and a phosphoric acid frequently lose their activities during polymerization use and also suffer a marked decrease in crushing strength due to softening of the catalyst. Such softening of the catalyst also results in short catalyst life inasmuch as the catalyst towers become plugged during use. 5 We have found, however, that catalysts of high crushing strength may be produced by adding to the com'- posite of phosphoric acid and diatomaceous earth a relatively small amount of manganese oxide, hydroxide, or salt which is generally added in an amount of not more than and preferably from about 0.5 to about 5% by weight of the catalyst mixture. Such a catalyst containing a manganese compound also has a good crushing strength after it has been used in the polymerization reaction. Pym-phosphoric acid-diatomaceous earth catalysts to which the above indicated amounts of a manganese compound have been added and then the resultant composite has been dried and calcined, have been found to produce catalysts having a high crushing strength, said strength being much higher than that of similar catalyst material prepared in the absence of the added manganese compound. These catalysts have then been tested in converting propylene into propylene polymers in rotatable steel autoclaves and have been found to retain this high crushing strength after such polymerization use in which from 30 to 65% of the propylene charged is converted into liquid products.

The following examples of the preparation of catalysts comprised within the scope of this invention and the results obtained in their use for catalyzing the polymerization of propylene are characteristic, although the exact details set forth in these examples are not to be construed as imposing undue limitation upon the generally broad scope of the invention.

Table I shows comparative results obtained in autoclave tests on phosphoric acid-diatomaceous earth catalysts containing manganese. These catalyst activity tests were carried out by placing 10 grams of 5 x 5 mm. pellets of the catalyst and 100 grams of propane-propylene mixture (50-55% propylene content) in a rotatable steel autoclave of 850 cc. capacity rotated at a temperature of 450 F. for two hours. At the end of this time, determinations were made to indicate the percentage conversion of propylene into liquid polymers.

TABLE I Olefin polymerization activity and crushing strength results obtained on catalysts prepared from phosphoric acid, diatomaceous earth and manganese dioxide [Test conditions: 10 grams catalyst, 100 grams propane-propylene feed, (50-55 mole percent CJHB) two hours at 450 F. (232 C.) in 850 cc. rotating autoclave] As indicated in the above table, a commercial solid phosphoric acid catalyst prepared from diatomaceous earth and pyrophosphoric acid but containing no added manganese compound had a propylene polymerizing activity of 66% in the autoclave test but showed an after use crushing strength of only 5.4 pounds in comparison with a before use crushing strength of 11.4 pounds. Similarly, a diatomaceous earth phosphoric acid catalyst which had been given an additional calcination treatment for one hour at a temperature of 860 F. gave a propylene conversion of 48% and retained an after use crushing strength of 9.4 pounds which was considerably lower than the initial crushing strength of 16 pounds. The addition of 2% by weight of manganese dioxide to the diatomaceous earth-pyrophosphoric acid catalyst yielded a composite which after drying and calcination had a propylene polymerizing activity of 55 and an after use crushing strength of 24.8+ pounds in comparison with a before use crushing strength of.23.6 pounds. It is thus noted that the addition of this relatively small amount of manganese dioxide improved considerably the crushing strength of the resultant catalyst composite without reducing substantially its olefin polymerizing activity.

The above-mentioned catalyst into which the manganese dioxide was incorporated was prepared from 3 grams of M1102, 126.2 grams of ortho-phosphoric acid of H3PO'4 concentration, and 40 grams of diatomaceous earth. First the manganese dioxide was thoroughly dispersed in the phosphoric acid and then the diatomaceous earth was worked into the resultant mixture to form a paste-like composite, which was dried in air under a heat lamp, until the composite reached a consistency satisfactory for pressing into a pill mold which consisted of a steel plate of 5 mm. thickness containing holes each 5 mm. in diameter. The catalyst pills were dried for 30 minutes in the pill plate at a temperature of 392 F., they were then removed from the pill plate and dried for 30 minutes more at the same temperature. After a preliminary calcination at 500 F., the pills were finally calcined for one hour at a temperature of 860 F. to give dried catalyst particles with an average crushing strength before use of 23.6 pounds.

The composition of the resultant catalyst particles corresponded to 2% MnO2, 26.6% diatomaceous earth, and 71.4% of ortho-phosphoric acid, the ratio of ortho-phosphoric acid to diatomaceous earth being the same as with'the com,- mercial solid phosphoric acid catalyst, namely, 2.7.

We claim as our invention:

1. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of a phosphoric acid, a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese compound selected from the members of the group consisting of an oxide, a hydroxide, and a salt, pelleting the resultant mixture, and calcining the pellets at a temperature of from about 500 to about 1000 F.

2. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of aphosphoric acid, a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese oxide, pelleting the resultant mixture, and calcining the pellelts at a temperature of from about 500 to about 1000 F.

3. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of a phosphoric acid, a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese salt, pelleting the resultant mixture, and calcining the pellets at a temperature of from about 500 to about 1000 F.

4. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of a phosphoric acid, a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese sulfide, pelleting the resultant mixture, and cal- 7 cining the pellets at a temperature of from'about 500 to about 1000' F.

5. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of a phosphoric acid, diatomaceous earth, and from about 0.5 to about 10% by weight of a manganese halide to form a composite, pelleting said composite, and calcining the pellets at a temperature of from about 500 to about 1000 F.

6. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of a polyphosphoric acid, a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese compound selected from the members of the group consisting of an oxide, a hydroxide, and a salt, pelleting the resultant mixture, and calcining the pellets at a temperature of from about 500 to about 1000 F.

7. A process for manufacturing a solid catalyst which comprises mixing over 50% by weight of pyrophosphoric acid, a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese compound selected from the members of the group consisting of an oxide, a hydroxide, and a salt, pelleting the resultant mixture, and calcining the pellets at a temperature of from about 500 to about 1000 F.

8. A process for manufacturing a solid catalyst which comprises mixing from about 50 to about 75% by weight of a phosphoric acid, from about to about 49.5% by weight of a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese compound, selected from the members of the group consisting of an oxide, a hydroxide, and a salt to form a composite, pelleting said composite, and calcining the pellets at a temperature of from about 500 to about 1000 F.

9. A process for manufacturing a solid catalyst which comprises mixing from about 50 to about 75% by weight of a phosphoric acid, from about 15 to about 49.5% by weight of a siliceous adsorbent, and from about 0.5 to about 10% by weight of a manganese compound selected from the members of the group consisting of an oxide, a hydroxide, and a salt at a temperature of from about 50 to about 450 F. to form a composite,

shaping said composite into particles, drying said particles at a temperature of from about 200 to about 500 F., and calcining the dried particles at a temperature of from about 500 to about 1000 F. for a time of from about 0.25 to about 10 hours.

10. A process for manufacuring a solid catalyst which comprises mixing from about to about by weight of a polyphosphoric acid, from about 15 to about 49.5% by weight of diatomaceous earth, and from about 0.5 to about 10% by weight of a manganese oxide at a temperature of from about 50 to about 450 F. to form a composite, shaping said composite into particles, drying said particles at a temperature of from about 200 to about 500 F., and calcining the dried particles at a temperature of from about 500 to about 1000 F. for a time of from about 0.25 to about 10 hours.

11. A process for manufacturing a solid catalyst which comprises mixing from about 50 to about 75% by weight of a polyphosphoric acid, from about 15 to about 49.5% by weight of diatomaceous earth, and from about 0.5 to about 10% by weight of manganese dioxide at a temperature of from about 50 to about 450 F. to form a. composite, shaping said composite into particles, drying said particles at a temperature of from about 200 to about 500 F., and calcining the dried particles at a temperature of from about 500 to about 1000 F. for a time of from about 0.25 to about 10 hours.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,120,702 Ipatieif et al June 14, 1938 2,120,723 Watson June 14, 1938 2,212,995 Wassermann Aug. 27, 1940 2,231,452 Morrell Feb. 11, 1941 2,275,182 Ipatieff et al Mar. 3, 1942 2,425,493 Stapleton Aug. 12, 1943 2,446,619 Stewart et al Aug. 10, 1948 2,447,599 Schmerling Aug. 24, 1948 2,496,621 Deery Feb. 7, 1950 2,525,144 Mavity Oct. 10, 1950 

1. A PROCESS FOR MANUFACTURING A SOLID CATALYST WHICH COMPRISES MIXING OVER 50% BY WEIGHT OF A PHOSPHORIC ACID, A SILICEOUS ADSORBENT, AND FROM ABOUT 0.5 TO ABOUT 10% BY WEIGHT OF A MAGANESE COMPOUND SELECTED FROM THE MEMBERS OF THE GROUP CONSISTING OF AN OXIDE, A HYDROXIDE, AND A SALT, PELLETING THE RESULTANT MIXTURE, AND CALCINING THE PELLETS AT A TEMPERATURE OF FROM ABOUT 500* TO ABOUT 1000* F. 